Federal contaminated sites in Ontario
Ontario has 3,995 sites in Canada's Federal Contaminated Sites Inventory — 16% of the 24,426 sites nationwide. 620 are active, 3,278 are closed, and 97 are suspected. Reported federal expenditure on these sites totals $3.23B (30% of the national total), an average of $808K per site.
Open these sites on the interactive map
Status and priority
| Sites | Share | |
|---|---|---|
| Active | 620 | 16% |
| Suspected | 97 | 2.4% |
| Closed | 3,278 | 82% |
| Sites | Share | |
|---|---|---|
| High Priority for Action | 288 | 7.2% |
| Medium Priority for Action | 676 | 17% |
| Low Priority for Action | 450 | 11% |
| Not a Priority for Action | 446 | 11% |
| Insufficient Information | 79 | 2.0% |
Reported expenditure by fiscal year
Custodian departments in Ontario
| Custodian | Sites | Reported spend |
|---|---|---|
| Fisheries and Oceans Canada | 1,900 | $79.5M |
| Indigenous Services Canada | 734 | $248.9M |
| National Defence | 518 | $208.2M |
| Transport Canada | 203 | $91.0M |
| National Capital Commission | 168 | $35.4M |
| Environment and Climate Change Canada | 160 | $11.0M |
| Public Services and Procurement Canada | 96 | $27.8M |
| Correctional Service Canada | 48 | $9.0M |
| Agriculture and Agri-Food Canada | 41 | $2.2M |
| Parks Canada Agency | 40 | $12.5M |
Most common contaminant types
Most affected media
Largest sites by reported expenditure
Municipalities with the most sites
Ottawa (324) · Kenora, Unorganized (255) · The Archipelago (139) · Kingston (108) · Killarney (100) · Thunder Bay, Unorganized (88) · Georgian Bay (82) · Essa (76) · Northeastern Manitoulin and the Islands (67) · Parry Sound, Unorganized, Centre Part (67) · Pickering (65) · Carling (62) · Toronto (55) · Norfolk County (44) · Thunder Bay (44) · Northern Bruce Peninsula (42) · Muskoka Lakes (40) · Adjala-Tosorontio (39) · Algoma, Unorganized, North Part (39) · Quinte West (38)
Figures are computed from the official FCSI open-data export published August 3, 2026, under the Open Government Licence – Canada. This is an unofficial site — verify against the official inventory before relying on details.